Wiring substrate and manufacturing method of wiring substrate

ABSTRACT

A wiring substrate includes a core, a first wiring layer formed on a first surface of the core, a second wiring layer formed on a second surface of the core, and an electronic component partially accommodated in the cavity and including a projected portion projected from the first opening of the core. A first insulating layer covers a side surface of the electronic component and the first surface of the core and fills a portion of the cavity. A second insulating layer covers the first insulating layer. A third insulating layer covers the second surface of the core. The remainder of the cavity that is not filled with the first insulating layer is filled with the third insulating layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Application No. 2013-121872, filed on Jun. 10,2013, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to a wiring substrate and a manufacturingmethod of a wiring substrate.

BACKGROUND

Japanese Laid-Open Patent Publication No. 2011-216740 describes anexample of wiring substrate incorporating an electronic component suchas a semiconductor chip. The wiring substrate includes a core substratehaving a cavity, an electronic component arranged in the cavity, andbuild-up layers formed on the two opposite surfaces of the coresubstrate. The electronic component is encapsulated in an insulativeresin material that fills the cavity. The electronic component iselectrically connected to wires in the build-up layers through viasformed in the build-up layers.

A manufacturing method of the wiring substrate will now be described.First, as illustrated in FIG. 12A, a cavity 90X is formed in a coresubstrate 90. A temporary fastening tape 91 is applied to a lowersurface 90A of the core substrate 90 to close the cavity 90X, and anelectronic component 92 is arranged on the tape 91 in the cavity 90X.Then, referring to FIG. 12B, vacuum lamination, vacuum hot pressing, orthe like is performed to fill the cavity 90X and cover an upper surface90B of the core substrate 90 with an insulating layer 93. Subsequently,as illustrated in FIG. 12C, the tape 91 is removed from the coresubstrate 90. Then, as illustrated in FIG. 12D, an insulating layer 94is stacked on the lower surface 90A of the core substrate 90, to whichthe tape 91 had been attached. Laser processing, for example, isperformed to form via holes VH11 and VH12 in the insulating layers 94and 93, respectively. Subsequently, a semi-additive process, forexample, is performed to form wiring layers 95 and 96. Then, a certainnumber of insulating layers and wiring layers are stacked on theinsulating layers 94 and 93.

SUMMARY

When the volume of the cavity 90X accommodating the electronic component92 increases, the insulating layer 93 may not be able to sufficientlyfill the cavity 90X. In such a case, dishing may occur in the insulatinglayer 93 immediately above the cavity 90X. This may adversely affect theformation of the wiring layer 96 on the insulating layer 93.

One aspect of the present disclosure is a wiring substrate including acore. The core includes a first surface, a second surface, and a cavity.The second surface is located at an opposite side of the first surface,and the cavity includes a first opening in the first surface and asecond opening in the second surface. A first wiring layer is formed onthe first surface of the core. A second wiring layer is formed on thesecond surface of the core. An electronic component is partiallyaccommodated in the cavity and includes a projected portion projectedfrom the first opening of the core. A first insulating layer covers atleast a portion of a side surface of the electronic component and thefirst surface of the core and fills a portion of the cavity. A portionof the cavity is filled with the first insulating layer. A secondinsulating layer covers a first surface of the first insulating layer. Afirst via wire extends through the second insulating layer. A thirdinsulating layer covers the second surface of the core. The remainder ofthe cavity that is not filled with the first insulating layer is filledwith the third insulating layer. A third wiring layer is formed on thesecond insulating layer and electrically connected to the electroniccomponent through at least the first via wire. A second via wire extendsthrough the third insulating layer. A fourth wiring layer is formed onthe third insulating layer and electrically connected to the secondwiring layer through the second via wire.

Other aspects and advantages of the present invention will becomeapparent from the following description, taken in conjunction with theaccompanying drawings, illustrating by way of example the principles ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with objects and advantages thereof, may best beunderstood by reference to the following description of the presentlypreferred embodiments together with the accompanying drawings in which:

FIG. 1 is a schematic cross-sectional view of a semiconductor deviceincluding a wiring substrate of a first embodiment taken along line 1-1in FIG. 2;

FIG. 2 is a schematic view of a portion of the semiconductor deviceincluding the wiring substrate of the first embodiment;

FIGS. 3A to 3D are schematic cross-sectional views illustrating amanufacturing method of the wiring substrate of the first embodiment;

FIGS. 4A, 4C, and 4D are schematic cross-sectional views illustratingthe manufacturing method of the wiring substrate of the firstembodiment;

FIG. 4B is a schematic plan view illustrating the manufacturing methodof the wiring substrate of the first embodiment;

FIGS. 5A and 5B are schematic cross-sectional view illustrating themanufacturing method of the wiring substrate of the first embodiment;

FIG. 5C is a schematic cross-sectional view illustrating a manufacturingmethod of a semiconductor device in the first embodiment;

FIGS. 6A to 6D, 7A, and 7B are schematic cross-sectional viewsillustrating a manufacturing method of a wiring substrate of a firstmodification;

FIG. 7C is a schematic cross-sectional view illustrating themanufacturing method of a semiconductor device including the wiringsubstrate of the first modification;

FIGS. 8A to 8D are schematic cross-sectional views illustrating amanufacturing method of a wiring substrate of a second modification;

FIG. 9A is a schematic cross-sectional view illustrating a manufacturingmethod of a wiring substrate of a third modification;

FIG. 9B is a schematic cross-sectional view illustrating a manufacturingmethod of a wiring substrate of a fourth modification;

FIGS. 10A to 10C are schematic cross-sectional views illustrating amanufacturing method of a wiring substrate of a fifth modification;

FIGS. 11A to 11D are schematic cross-sectional views illustrating amanufacturing method of a wiring substrate of a sixth modification;

FIGS. 12A to 12D are schematic cross-sectional views illustrating amanufacturing method of a wiring substrate of the related art.

DETAILED DESCRIPTION OF EMBODIMENTS

In the drawings, elements are illustrated for simplicity and clarity andhave not necessarily been drawn to scale. To facilitate understanding,hatching lines may not be illustrated in the cross-sectional drawingsand screentones may be used instead.

As illustrated in FIG. 1, a semiconductor device 10 includes a wiringsubstrate 20, a semiconductor chip 11 mounted on the wiring substrate20, and an underfill resin 15 formed in a gap between the wiringsubstrate 20 and the semiconductor chip 11.

The wiring substrate 20 includes a core 21, a chip capacitor 40incorporated in the wiring substrate 20, an insulating layer 45 thatcovers the first surface 35A (e.g., upper surface) of the core 21, awiring structure 22 formed on a first surface 45A of the insulatinglayer 45, a wiring structure 23 formed on a second surface 36B of thecore 21, a solder resist layer 24 that covers the wiring structure 22,and a solder resist layer 25 that covers the wiring structure 23.

The core 21 is, for example, a multi-layer printed wiring board. Thecore 21 includes a core substrate 31, inner wiring layers 32 and 33,insulating layers 35 and 36, outer wiring layers 37 and 38, andthrough-core electrodes 39. Each of the outer wiring layers 37 and 38serve as the outer surface of the core 21. In the illustrated example,the first surface 35A of the core 21 corresponds to the outer surface ofthe insulating layer 35, and a second surface 36B of the core 21corresponds to the outer surface of the insulating layer 36. Thethickness of the core 21 conforms to the distance from the first surface35A of the insulating layer 35 to the second surface 36B of theinsulating layer 36 and is, for example, about 300 to 800 μm.

The core substrate 31 may be a so-called glass epoxy substrate that isformed by impregnating, for example, a glass cloth (glass woven cloth),which is a reinforcement material, with a thermosetting insulativeresin, of which the main component is epoxy resin, and then hardeningthe glass cloth. The reinforcement material is not limited to glasscloth, and may be, for example, glass nonwoven cloth, aramid wovencloth, aramid nonwoven cloth, liquid crystal polymer (LAP) woven cloth,or LAP nonwoven cloth. The thermosetting insulative resin may be aninsulative resin other than the epoxy resin such as polyimide resin,cyanide resin, or the like.

The wiring layer 32 is formed on a first surface (e.g., upper surface)of the core substrate 31, and the wiring layer 33 is formed on a secondsurface (e.g., lower surface) of the core substrate 31. The wiringlayers 32 and 33 include, for example, a power line and a ground line.The insulating layer 35 covers the wiring layer 32, which is stacked onthe first surface of the core substrate 31. The insulating layer 36covers the wiring layer 33, which is stacked on the second surface ofthe core substrate 31. The wiring layers 32 and 33 may be formed from,for example, copper or copper alloy. The insulating layers 35 and 36 maybe formed from, for example, an insulative resin such as epoxy resin,polyimide resin, or the like, a composite resin material, in which afiller such as silica, alumina, and the like is mixed with theinsulative resin.

Through holes 21X are formed at certain locations (two locations inFIG. 1) in the core 21 (core substrate 31 and insulating layers 35 and36). Each through hole 21X extends through the core substrate 31 and theinsulating layers 35 and 36 in a thicknesswise direction. Each throughhole 21X receives one of the through-core electrodes 39. Thethrough-core electrode 39 is, for example, rod-shaped. The through-coreelectrode 39 has a diameter of, for example, about 50 to 100 μm. Thematerial of the through-core electrode 39 is, for example, copper orcopper alloy.

The wiring layer 37 is formed on the first surface 35A of the insulatinglayer 35 (first surface 35A of the core 21). The wiring layer 38 isformed on the second surface 36B of the insulating layer 36 (secondsurface 36B of the core 21). The through-core electrodes 39 electricallyconnect the wiring layers 37 and 38.

As illustrated in FIG. 2, the wiring layers 37 and 38 are formed to be,for example, substantially circular as viewed from above. The wiringlayers 37 and 38 each have a diameter of, for example, about 100 to 150μm. The wiring layers 37 and 38 each have a thickness of, for example,about 10 to 20 μm. The wiring layers 37 and 38 are formed from, forexample, copper or copper alloy. FIG. 2 is a schematic view of the core21, the chip capacitor 40, and the insulating layer 45 taken from theupper side in FIG. 1.

As illustrated in FIG. 1, the core 21 (core substrate 31 and insulatinglayers 35, 36) includes a cavity 21Y formed at a certain location (e.g.,one location). The cavity 21Y extends through the core 21 (coresubstrate 31 and insulating layers 35 and 36) in the thicknesswisedirection. Further, the cavity 21Y has a first opening in the firstsurface 35A of the core 21 and a second opening in the second surface36B of the core 21. The cavity 21Y may be referred to as anaccommodation compartment for accommodating the chip capacitor 40.

In the example illustrated in FIG. 2, the cavity 21Y is formed in acentral portion of the core 21. The cavity 21Y is shaped in conformancewith the chip capacitor 40 and may be, for example, rectangular asviewed from above. The cavity 21Y has a larger footprint than the chipcapacitor 40. Thus, the chip capacitor 40 may be arranged away towardthe inner side from the wall surface of the cavity 21Y. The cavity 21Ymay be, for example, 5 mm×5 mm to 15 mm×15 mm as viewed from above.

As illustrated in FIG. 1, most of the chip capacitor 40 is arranged inthe cavity 21Y and the remainder of the chip capacitor 40 projects fromthe first opening of the cavity 21Y and is arranged in the insulatinglayer 45. The chip capacitor 40 may include a box-shaped capacitor body41 and two connection terminals 42, which are formed at the twolongitudinal ends of the capacitor body 41. Each connection terminal 42covers at least a side surface, which includes one end face in thelongitudinal direction of the capacitor body 41, a portion of the uppersurface, and a portion of the lower surface.

The chip capacitor 40 has a thickness of, for example, 200 to 500 μm.The capacitor body 41 is mainly formed by, for example, an electrode ofceramics, copper, or the like. The connection terminals 42 are formedfrom, for example, copper or copper alloy.

The chip capacitor 40 projects toward the upper side from the firstopening of the cavity 21Y, that is, the core 21, or the first surface35A of the insulating layer 35. Accordingly, a portion of the capacitorbody 41, the entire first surface 42A of the connection terminal 42, anda portion of the side surface of each connection terminal 42 projecttoward the upper side from the first opening of the cavity 21Y. In theillustrated example, the first surface 42A of each connection terminal42 is located above the first surface 35A of the insulating layer 35.Further, the first surface 42A of each connection terminal 42 is flushwith a first surface 37A of the wiring layer 37. The first surface 42Aof each connection terminal 42 and the first surface 37A of the wiringlayer 37 is substantially flush with the first surface 45A (e.g., uppersurface) of the insulating layer 45.

The surface of the chip capacitor 40 exposed from the insulating layer45, that is, the first surface 42A of each connection terminal 42, arerough surfaces. In the preferred example, the first surface 42A of eachconnection terminal 42 is rougher than the surfaces of the chipcapacitor 40 covered by the insulating layer 45.

The cavity 21Y is filled with two insulating layers, namely theinsulating layer 45 and an interlayer insulating layer 61. Theinsulating layer 45 fills a portion of the cavity 21Y and covers thefirst surface 35A of the core 21. In the illustrated example, theinsulating layer 45 entirely covers the first surface 35A of the core 21exposed from the wiring layer 37. Further, the insulating layer 45covers a portion of the chip capacitor 40. In the illustrated example,the insulating layer 45 covers the second surface 42B of each connectionterminal 42, the side surfaces of each connection terminal 42, and theentire capacitor body 41 exposed from the connection terminals 42.Accordingly, in the chip capacitor 40, the portion of each connectionterminal 42 excluding the first surface 42A is buried on the insulatinglayer 45, and only the first surface 42A of the connection terminal 42of the chip capacitor 40 is exposed from the insulating layer 45. Theinsulating layer 45 may formed from an insulative resin such as epoxyresin or polyimide resin. The thickness from the first surface 35A(e.g., upper surface) of the insulating layer 35 to the first surface45A (e.g., upper surface) of the insulating layer 35 is, for example, 15to 35 μm.

The wiring structure 22 is stacked on the first surface 45A of theinsulating layer 45. In the wiring structure 22, wiring layers andinterlayer insulating layers are alternately stacked. The wiring layermay have any number of layers. The interlayer insulating layer has athickness that insulates the wiring layers from each other. In thewiring structure 22 of the present example, the interlayer insulatinglayer 51, a wiring layer 52, an interlayer insulating layer 53, a wiringlayer 54, an interlayer insulating layer 55, and a wiring layer 56 arestacked in this order.

The interlayer insulating layer 51 is formed on the insulating layer 45and the insulating layer 45. The interlayer insulating layer 51 coversthe first surface 42A of each connection terminal 42, the first surface37A of the wiring layer 37, and the first surface 45A of the insulatinglayer 45. The material of the interlayer insulating layer 51 is, forexample, an insulative resin such as epoxy resin or polyimide resin, ora composite resin material in which a filler such as silica, alumina, orthe like is mixed with the insulative resin. The thickness from thefirst surface 37A of the wiring layer 37 to the first surface 51A (e.g.,upper surface) of the interlayer insulating layer 51 is, for example, 15to 35 μm.

The interlayer insulating layer 51 includes via holes VH1 extendingthrough the interlayer insulating layer 51 to expose the first surface37A of the wiring layer 37 or the first surface 42A of the connectionterminal 42. The via holes VH1 may be referred to as first via holes.

The wiring layer 52 is stacked on the interlayer insulating layer 51.The wiring layer 52 is electrically connected to the wiring layer 37 orthe connection terminal 42 through via wires 57 filled in the via holeVH1. In other words, the wiring layer 52 is electrically connected tothe wiring layer 37 or the connection terminal 42 through the via wires57 extending through the interlayer insulating layer 51.

In the same manner, the interlayer insulating layer 53 is formed on theinterlayer insulating layer 51 to cover the wiring layer 52. The wiringlayer 54 is formed on the interlayer insulating layer 53 andelectrically connected to the wiring layer 52 through via wires 58extending through the interlayer insulating layer 53. The interlayerinsulating layer 55, which is the outermost layer, is formed on theinterlayer insulating layer 53 to cover the wiring layer 54. Theoutermost wiring layer 56 is formed on the interlayer insulating layer55 and electrically connected to the wiring layer 54 through via wires59 extending through the interlayer insulating layer 55.

The via wires 57, 58, and 59 are tapered so that the diameter increasesfrom the lower side (core 21) toward the upper side (outermost wiringlayer 56) as viewed in FIG. 1. Each of the via wires 57, 58, and 59 are,for example, shaped into the forms of rods or truncated cones and has adiameter of 50 to 75 μm. Each of the wiring layers 52, 54, 56 has athickness of, for example, 15 to 35 μm. The thickness from the firstsurface (e.g., upper surface) of the wiring layer 52 to the firstsurface (e.g., upper surface) of the interlayer insulating layer 53 andthe thickness from the first surface (e.g., upper surface) of the wiringlayer 54 to the first surface (e.g., upper surface) of the interlayerinsulating layer 55 are, for example, about 15 to 35 μm. The wiringlayers 52, 54, and 56 and the via wires 57, 58, and 59 may be formedfrom, for example, copper or copper alloy. The interlayer insulatinglayers 53 and 55 may be formed from, for example, an insulative resinsuch as epoxy resin or polyimide resin, or a composite resin material inwhich a filler such as silica, alumina, and the like is mixed with theinsulative resin.

The solder resist layer 24 is stacked on the first surface (e.g., uppersurface) of the interlayer insulating layer 55 of the outermost layer(e.g., uppermost layer). The solder resist layer 24 is formed from, forexample, an insulative resin such as epoxy resin, acryl resin, or thelike. The solder resist layer 24 includes openings 24X exposing portionsof the wiring layer 56 of the uppermost layer as pads P1. Each pad P1 isflip-chip connected to a bump 12 of the semiconductor chip 11. In thewiring substrate 20, the surface on which the pads P1 are formedfunctions as a chip mounting surface.

When necessary, an Organic Solderability Preservative (OSP) process maybe performed on the wiring layer 56 exposed from the opening 24X to forman OSP film, and the semiconductor chip 11 may be connected to the OSPfilm. A metal layer may be formed on the wiring layer 56 exposed fromthe opening 24X, and the semiconductor chip 11 may be connected to themetal layer. An example of the metal layer includes a gold (Au) layer, anickel (Ni) layer/Au layer (metal layer in which Ni layer and Au layerare stacked in this order on the wiring layer 56), an Ni layer/palladium(Pd) layer/Au layer (metal layer in which Ni layer, Pd layer, and Aulayer are stacked in this order on the wiring layer 56), and the like.The Ni layer, Au layer, and Pd layer may be metal layers(non-electrolytic plating metal layers) formed through anon-electrolytic plating process, for example. The Au layer is a metallayer including Au or Au alloy, the Ni layer is a metal layer includingNi or Ni alloy, and the Pd layer is a metal layer including Pd or Pdalloy.

The wiring structure 23 is stacked on the second surface 36B of theinsulating layer 36. In the wiring structure 23, the wiring layer andthe interlayer insulating layer are alternately stacked. The wiringlayer may have any number of layers. The interlayer insulating layer hasa thickness that insulates the wiring layers from each other. In thewiring structure 23 of the present example, an interlayer insulatinglayer 61, a wiring layer 62, an interlayer insulating layer 63, a wiringlayer 64, an interlayer insulating layer 65, and a wiring layer 66 arestacked in this order.

The interlayer insulating layer 61 fills the cavity 21Y in cooperationwith the insulating layer 45. The interlayer insulating layer 61 coversthe second surface 36B of the insulating layer 36, and a second surface38B (e.g., lower surface) of the wiring layer 38. The interlayerinsulating layer 61 is formed on second surface 45B (e.g., lowersurface) of the insulating layer 45 in the cavity 21Y to fill theportion of the cavity 21Y that is not filled with the insulating layer45. Accordingly, the interlayer insulating layer 61 fills the spaceformed by the second surface 45B of the insulating layer 45 and theinner walls of the cavity 21Y below the second surface 45B. Theinterlayer insulating layer 61 is preferably formed from, for example,an insulative resin having a higher insulating capability than theinterlayer insulating layer 51, and is, for example, an insulative resinsuch as epoxy resin or polyimide resin. The thickness from the secondsurface 38B of the wiring layer 38 to the second surface 61B of theinterlayer insulating layer 61 is, for example, set to be the same asthe thickness from the first surface 37A of the wiring layer 37 to thefirst surface 51A of the interlayer insulating layer 51 described above.In other words, the thickness of the insulating layer 45 and thicknessof the interlayer insulating layer 61 formed on the wiring layer 38 areset to be the same as the thickness of the interlayer insulating layer51 formed on the wiring layer 37. For example, the thickness from thesecond surface 38B of the wiring layer 38 to the second surface 61B ofthe interlayer insulating layer 61 is set to about 15 to 35 μm. Thesecond surface 45B of the insulating layer 45 may be referred to as theboundary plane of the insulating layer 45 and the interlayer insulatinglayer 61. The insulating layer 45 may be referred to as the upper resinlayer, and the interlayer insulating layer 61 may be referred to as thelower resin layer.

Via holes VH2 extend through the interlayer insulating layer 61 in thethicknesswise direction of the interlayer insulating layer 61 to exposethe second surface 38B of the wiring layer 38. The via holes VH2 may bereferred to as the second via holes.

The wiring layer 62 is stacked on the second surface 61B of theinterlayer insulating layer 61. The wiring layer 62 is electricallyconnected to the wiring layer 38 through via wires 67 filled in the viaholes VH2. The wiring layer 62 is electrically connected to the wiringlayer 38 through the via wires 67 extending through the interlayerinsulating layer 61 and the insulating layer 45.

In the same manner, the interlayer insulating layer 63 is formed on thesecond surface 61B of the interlayer insulating layer 61 so as to coverthe wiring layer 62. The wiring layer 64 is formed on the second surface(e.g., lower surface) of the interlayer insulating layer 63 and iselectrically connected to the wiring layer 62 through via wires 68extending through the interlayer insulating layer 63. The interlayerinsulating layer 65, which is the outermost layer, is formed on thesecond surface of the interlayer insulating layer 63 to cover the wiringlayer 64. The wiring layer 66 of the outermost layer is formed on thesecond surface (e.g., lower surface) of the interlayer insulating layer65 and electrically connected to the wiring layer 64 through via wires69 extending through the interlayer insulating layer 65.

The via wires 67, 68, and 69 are tapered so that the diameter increasesfrom the upper side (core 21) toward the lower side (wiring layer 66) asviewed in FIG. 1. Each of the via wires 67, 68, and 69 are, for example,shaped into the forms of rods or truncated cones and has a diameter of50 to 75 μm. The thickness of the wiring layers 62, 64, 66 is, forexample, 15 to 35 μm. The thickness from the second surface of thewiring layer 62 to the second surface of the interlayer insulating layer63 and the thickness from the second surface of the wiring layer 64 tothe second surface of the interlayer insulating layer 65 are, forexample, about 15 to 35 μm. The wiring layers 62, 64, and 66 and the viawires 67, 68, 69 may be formed from, for example, copper or copperalloy. The interlayer insulating layers 63, 65 may be formed from, forexample, an insulative resin such as epoxy resin, polyimide resin, andthe like, or a composite resin material in which a filler such assilica, alumina, and the like is mixed with the insulative resin.

The solder resist layer 25 is stacked on the second surface (e.g., lowersurface) of the interlayer insulating layer 65, which is the outermostlayer (e.g., lowermost layer). The solder resist layer 25 may be formedfrom, for example, an insulative resin such as epoxy resin, acryl resin,and the like. The solder resist layer 25 includes openings 25X thatexpose portions of the second surface (e.g., lower surface) of thewiring layer 66 of the lowermost layer as external connection pads P2.Each external connection pad P2 is connected to an external connectionterminal 16 such as a solder ball, a lead pin, and the like that is usedwhen mounting the semiconductor device 10 to a mounting substrate suchas a motherboard, and the like. When necessary, an OSP process may beperformed on the wiring layer 66 exposed from the openings 25X to forman OSP film, and the external connection terminals 16 may be connectedto the OSP film. A metal layer may be formed on the wiring layer 66exposed from the openings 25X, and the external connection terminals 16may be connected to the metal layer. An example of the metal layerincludes an Au layer, a Ni layer/Au layer (metal layer in which Ni layerand Au layer are stacked in this order on the second surface of thewiring layer 66), an Ni layer/Pd layer/Au layer (metal layer in which Nilayer, Pd layer, and Au layer are stacked in this order on the secondsurface of the wiring layer 66), and the like. The wiring layer 66 (OSPfilm or metal layer when the OSP film and the metal layer are formed onthe wiring layer 66) exposed from the openings 25X may function as theexternal connection terminals.

The semiconductor chip 11 is flip-chip mounted on the wiring substrate20. In other words, the bumps 12 arranged on the circuit forming surface(lower surface in FIG. 1) of the semiconductor chip 11 are joined withthe pads P1 of the wiring substrate 20. The bumps 12 electricallyconnect the semiconductor chip 11 to the wiring layer 56 of the wiringsubstrate 20.

The semiconductor chip 11 may be, for example, a logic chip such as aCentral Processing Unit (CPU) chip, a Graphics Processing Unit (GPU)chip, or the like. Further, the semiconductor chip 11 may be, forexample, a memory chip such as a Dynamic Random Access Memory (DRAM)chip, a Static Random Access Memory (SRAM) chip, a flash memory chip, orthe like. The size of the semiconductor chip 11 may be, for example,about 3 mm×3 mm to 12 mm×12 mm as viewed from above. The semiconductorchip 11 has a thickness of, for example, about 50 to 100 μm.

Each bump 12 may be, for example, a gold bump or a solder bump. Thesolder bump may be formed from, for example, an alloy containing lead(Pb), alloy of tin (Sn) and Au, alloy of Sn and Cu, alloy of Sn and Ag,alloy of Sn, Ag, and Cu, or the like.

The underfill resin 15 fills the gap between the first surface (e.g.,upper surface) of the wiring substrate 20 and the second surface (e.g.,lower surface) of the semiconductor chip 11. The underfill resin 15 maybe formed from, for example, an insulative resin such as epoxy resin orthe like.

The operation of the semiconductor device 10 will now be described.

The cavity 21Y is filled with two insulating layers, namely, theinsulating layer 45 and the interlayer insulating layer 61. For example,when forming the insulating layer 45 and the interlayer insulating layer61 in different steps, before forming one of the insulating layers(e.g., interlayer insulating layer 61) in a latter step, the cavity 21Yis already partially filled with the other one of the insulating layers(e.g., insulating layer 45). Thus, even if the volume of the cavity 21Yincreases, the volume of the space that is to be filled in the latterstep by one of the insulating layers (e.g., interlayer insulating layer61) is relatively small. Accordingly, compared to when filling thecavity 21Y having the same volume with a single insulating layer, theamount of each of the two insulating layers 45 and 61 may be reduced.Further, the two insulating layers 45 and 61 are able to fill the cavity21Y in a preferable manner.

A manufacturing method of the wiring substrate 20 will now be describedwith reference to FIGS. 3A to 5C.

As illustrated in FIG. 3A, the core 21 that includes the cavity 21Y isfirst prepared. The core 21 may be manufactured, for example, asdescribed below. Using the known art, a printed wiring board may beformed including the core substrate 31 and the wiring layers 32 and 33and the insulating layers 35 and 36 respectively formed on the firstsurface (e.g., lower surface) and the second surface (e.g., uppersurface) of the core substrate 31, the wiring layers 37 and 38respectively formed on the outer surfaces of the insulating layers 35and 36, and the through-core electrodes 39. Then, the cavity 21Y isformed to open at locations corresponding to the mounting position ofthe chip capacitor 40 (see FIG. 1) in the formed printed wiring board.This completes the core 21. The cavity 21Y may be formed, for example,by performing router processing, die processing that uses a die, laserprocessing, drilling, or the like.

As illustrated in FIG. 3A, an adhesive sheet or an adhesive tape 70including a film or a tape base 71 and an adhesive layer 72 applied toan upper surface 71A of the tape base 71 is prepared. The adhesive tape70 is preferably formed from, for example, a material having superiorchemical resistance and heat resistance. The tape base 71 may be formedfrom a material having satisfactory workability, for example, apolyimide resin or a polyester resin. The adhesive layer 72 is a viscousinsulating layer and forms the insulating layer 45 when processed in asubsequent step. The adhesive layer 72 may be formed from, for example,an insulative resin such as an epoxy resin or a polyimide resin. Theadhesive layer 72 is in a B-stage state (semi-cured state). The tapebase 71 may have a thickness of, for example, about 30 to 50 μm. Theadhesive layer 72 may have a thickness of, for example, 30 to 50 μm.

As illustrated in FIG. 3A, the adhesive tape 70 is arranged on the firstsurface 35A of the core 21 opposing the first surface 35A of theinsulating layer 35. In the illustrated example, the adhesive tape 70 isarranged with the adhesive layer 72 facing upward so that the adhesivelayer 72 faces the core 21.

Then, as illustrated in FIG. 3B, the adhesive tape 70 is applied to thefirst surface 37A of the wiring layer 37 on the core 21. The adhesivelayer 72 of the adhesive tape 70 is applied to the first surface 37A ofthe wiring layer 37. However, it is preferable that a gap be formedbetween the adhesive tape 70 and the insulating layer 35 of the core 21.For example, the adhesive tape 70 is laminated to the first surface 37Aof the wiring layer 37 through thermal compression bonding. Under thissituation, the adhesive layer 72 is still in the B-stage state.

Then, as illustrated in FIG. 3C, using, for example, a mounter, the chipcapacitor 40 is mounted on the adhesive layer 72 of the adhesive tape 70exposed in the cavity 21Y of the core 21.

Subsequently, referring to FIG. 3D, when the structure illustrated inFIG. 3C is heated to 110° C. to 160° C., the chip capacitor 40 and thecore 21 are pressed against the adhesive tape 70 (adhesive layer 72). Asa result, the first surface 35A of the core 21, the first surface 37A ofthe wiring layer 37, the first surface 41A of the capacitor body 41, andthe first surface 42A of each connection terminal 42 press the adhesivelayer 72, which is in the semi-cured state. This spreads the adhesivelayer 72 in the planar direction. The spread adhesive layer 72 entersthe cavity 21Y so that the space between the chip capacitor 40 and thewall of the cavity 21Y is partially filled with the adhesive layer 72.In the illustrated example, the adhesive layer 72 in the cavity 21Yentirely covers the chip capacitor 40. In this manner, when the chipcapacitor 40 is pressed against the adhesive layer 72, the chipcapacitor 40 is entirely buried in the semi-cured adhesive layer 72. Inthis step, the chip capacitor 40 and the core 21 are pressed against theadhesive tape 70 until the first surface 42A of each connection terminal42 and the first surface 37A of the wiring layer 37 contacts the uppersurface 71A of the tape base 71.

Then, the adhesive layer 72 undergoes, for example, a thermosettingprocess. This thermally cures the adhesive layer 72 that forms theinsulating layer 45. In one example, the insulating layer 45 entirelycovers the chip capacitor 40, and the second surface 45B (e.g., uppersurface) of the insulating layer 45 is located above the second surface42B of each connection terminal 42. By thermally curing the adhesivelayer 72, the insulating layer 45, the core 21, and the chip capacitor40 are adhered and integrated to one another.

As illustrated in FIG. 4A, the tape base 71 of the adhesive tape 70 isremoved from the core 21 so that the insulating layer 45 remains adheredto the core 21 and the chip capacitor 40. The insulating layer 45 coversthe first surface 35A of the insulating layer 35, portions of the wallsof the cavity 21Y, side surfaces of the wiring layer 37, the secondsurface 42B and side surfaces of each connection terminal 42, and theentire surface of the capacitor body 41 exposed from each connectionterminal 42. The first surface 42A of each connection terminal 42 andthe first surface 37A of the wiring layer 37, which come into contactwith the upper surface 71A of the tape base 71 in the step of FIG. 3D,are exposed from the insulating layer 45.

As illustrated in FIG. 4A, the first surface 42A of each connectionterminal 42 projects toward the lower side from the first surface 35A ofthe core 21. Further, the first surface 45A of the insulating layer 45,the first surface 42A of each connection terminal 42, and the firstsurface 37A of the wiring layer 37 are substantially flush with oneanother extending along the upper surface 71A of the tape base 71 andform a flat plane.

In this manner, the adhesive layer 72 on the tape base 71 is not removedfrom the core 21 and is used as the insulating layer 45. Thus, in theillustrated example, the first surface 45A of the insulating layer 45 isformed on the same plane as the first surface 42A of each connectionterminal 42. In another example, the first surface 45A is formed belowthe first surface 42A.

Subsequently, a roughening process is performed on the connectionterminals 42 and the wiring layer 37 exposed from the insulating layer45. The roughening process is performed to set the surface roughness Raof the first surface 42A of each connection terminal 42 and the firstsurface 37A of the wiring layer 37 to about 0.5 to 2 μm. The surfaceroughness Ra is also referred to as the arithmetic average roughness,which is an arithmetic average value of the height (absolute value) fromthe average surface level measured at various positions within apredetermined measurement region. In the present step, fine pits andvalleys are formed in the first surface 42A of each connection terminal42 and the first surface 37A of the wiring layer 37 to roughen the firstsurface 42A of each connection terminal 42 and the first surface 37A ofthe wiring layer 37. The roughening process is performed so that theinterlayer insulating layer 51 is easily adhered to the connectionterminal 42 and the wiring layer 37 in the next step illustrated in FIG.4C. The roughening process may be, for example, an etching process, a CZprocess, a blackening process (oxidation process), and a sandblastprocess. The roughening process also eliminates the residual of theremoved tape base 71 from the first surface 42A of each connectionterminal 42 and the first surface 37A of the wiring layer 37.

Then, as illustrated in FIG. 4C, the interlayer insulating layer 51 isformed on the first surface 45A of the insulating layer 45 to cover thefirst surface 45A of the insulating layer 45, the first surface 42A ofeach connection terminal 42, and the first surface 37A of the wiringlayer 37. In the this step, the cavity 21Y exposed from the insulatinglayer 45 (for example, space formed by the second surface 45B of theinsulating layer 45 and the wall located above the insulating layer 45in the cavity 21Y) is filled with the interlayer insulating layer 61,which also covers the second surface 36B of the insulating layer 36 andthe wiring layer 38. The cavity 21Y is partially filled with theinsulating layer 45. Thus, the volume of the space filled with theinsulating layer 61 is relatively small. Thus, even when the cavity 21Yhas a large volume, the cavity 21Y may be filled with the interlayerinsulating layer 61 in a further preferable manner than the related art.This prevents or reduces dishing in the interlayer insulating layer 61above the cavity 21Y and flattens the second surface 61B of theinterlayer insulating layer 61. The interlayer insulating layers 51 and61 are formed through, for example, vacuum lamination or vacuumpressing.

In the present step, the chip capacitor 40 is buried in the insulatinglayer 45. This obviates displacement or the like of the chip capacitor40 that would be caused by displacement of the pressure of the resin(resin for forming the interlayer insulating layer 61) flowing into thecavity 21Y. In the present manufacturing method, the insulating layer 45(adhesive layer 72) is not removed and remains adhered to the chipcapacitor 40 and the core 21. Under this situation, a further insulatinglayer, that is, the interlayer insulating layer 51, is stacked on thefirst surface 45A of the insulating layer 45. This omits the step forremoving the insulating layer 45 (adhesive layer 72) and obviates theformation of an adhesive residual 91A (FIG. 12C) that may occur duringremoval of the adhesive layer 72.

In the present step, the thickness of the interlayer insulating layer 51and the thickness of the interlayer insulating layer 61 are set so thatthe thickness T1 from the first surface 37A of the wiring layer 37 tothe first surface 51A (e.g., lower surface) of the interlayer insulatinglayer 51 is substantially equal to the thickness T2 from the secondsurface 38B of the wiring layer 38 to the second surface 61B (e.g.,upper surface) of the interlayer insulating layer 61. For example, whenthe thickness of each of the wiring layers 37 and 38 is 10 μm, thethickness of the interlayer insulating layer 51 is set to 25 μm and thethickness from the second surface 36B of the insulating layer 36 to thesecond surface 61B of the interlayer insulating layer 61 is set to 35μm. This sets both of the thickness T1 and the thickness T2 to about 25μm. By setting the thickness T1 to be the same as the thickness T2, thehandling characteristics for forming wiring layers in subsequent stepsmay be improved.

Then, as illustrated in FIG. 4D, the via holes VH1 are formed at certainlocations in the interlayer insulating layer 51 to expose portions ofthe first surface 37A of the wiring layer 37 and portions of the firstsurface 42A of each connection terminal 42. The via holes VH2 are formedat certain locations in the interlayer insulating layer 61 to exposeportions of the second surface 38B of the wiring layer 38. The via holesVH1 and VH2 may be formed through laser processing using, for example,CO₂ laser, UV-YAG laser, or the like. If the insulating layer 45 and theinterlayer insulating layers 51 and 61 are formed using a photosensitiveresin, the via holes VH1 and VH2 may be formed through, for example,photolithography.

When the via holes VH1 and VH2 are formed in a laser processing method,a desmear process is carried out to remove resin smear from the surfacesof the wiring layers 37 and 38 and the connection terminals 42 exposedat the bottom of the via holes VH1 and VH2.

Then, as illustrated in FIG. 5A, the via wires 57 are formed in the viaholes VH1, and the wiring layer 52 electrically connected to the wiringlayer 37 or the connection terminals 42 through the via wires 57 isstacked on the first surface 51A of the interlayer insulating layer 51.Further, the via wires 67 are formed in the via holes VH2, and thewiring layer 62 electrically connected to the wiring layer 38 throughthe via wires 67 is stacked on the second surface 61B of the interlayerinsulating layer 61. The via wires 57 and 67 and the wiring layers 52and 62 may be formed using various wire formation methods such as asemi-additive process, a subtractive process, or the like.

Then, as illustrated in FIG. 5B, the procedures of FIGS. 4C to 5A arerepeated to alternately stack the interlayer insulating layers 53 and 55and the wiring layers 54 and 56 on the first surface 51A of theinterlayer insulating layer 51, and to alternately stack the interlayerinsulating layers 63 and 65 and the wiring layers 62 and 64 on thesecond surface 61B of the interlayer insulating layer 61.

Subsequently, the solder resist layer 24 including the openings 24X forexposing the pads P1, formed at certain locations in the wiring layer56, is stacked on the first surface 55A (e.g., lower surface) of theinterlayer insulating layer 55. The solder resist layer 25 including theopenings 25X for exposing the external connection pads P2, formed atcertain locations in the wiring layer 66, is stacked on the secondsurface 65B (e.g., upper surface) of the interlayer insulating layer 65.The solder resist layers 24 and 25 may be formed, for example, bylaminating a photosensitive solder resist film or applying a liquidsolder resist and then patterning the resist to a certain shape. Thisexposes portions of the wiring layer 56 from the openings 24X of thesolder resist layer 24 as the pads P1. This also exposes portions of thewiring layer 66 from the openings 25X of the solder resist layer 25 asthe external connection pads P2. When necessary, a metal layer in which,for example, an Ni layer and an Au layer are stacked in this order maybe formed on the pads P1 and the external connection pads P2. Such ametal layer may be formed, for example, through a non-electrolyticplating method. The wiring substrate 20 of FIG. 1 is manufacturedthrough the above manufacturing steps.

A manufacturing method of the semiconductor device 10 will now bedescribed with reference to FIG. 5C. The structure illustrated in FIG.5C is reversed upside down from the structure illustrated in FIG. 5B.

As illustrated in FIG. 5C, the semiconductor chip 11 is first mounted onthe wiring substrate 20, which is manufactured as described above. Forexample, the bumps 12 of the semiconductor chip 11 are flip-chip joinedwith the pads P1 of the wiring substrate 20. Then, the underfill resin15 is filled and cured between the wiring substrate 20 and thesemiconductor chip 11 that are flip-chip joined. The external connectionterminals 16 are formed on the external connection pads P2. For example,after applying flux to the external connection pads P2, the externalconnection terminal 16 (e.g., solder ball) are mounted on the externalconnection pads P2 and fixed by performing a reflow process under atemperature of 240° C. to 260° C. Then, the surface is washed to removethe flux.

The semiconductor device 10 of FIG. 1 is manufactured through themanufacturing steps described above.

The first embodiment has the advantages described above.

(1) The chip capacitor 40 is pressed into the adhesive layer 72 to burya portion of the chip capacitor 40 in the adhesive layer 72. This fillsa portion of the cavity 21Y with the adhesive layer 72 (insulating layer45). Then, the remainder of the cavity 21Y that is not filled with theinsulating layer 45 is filled with the interlayer insulating layer 61.Accordingly, a portion of the cavity 21Y is filled with the insulatinglayer 45 before filling the cavity 21Y with the interlayer insulatinglayer 61. Thus, the volume of the space filled with the interlayerinsulating layer 61 is relatively small. For this reason, even when thecavity 21Y has a large volume, the cavity 21Y may be filled with theinterlayer insulating layer 61 in a further preferable manner. Thisprevents or reduces dishing in the interlayer insulating layer 61 abovethe cavity 21Y and flattens the second surface 61B of the interlayerinsulating layer 61. Thus, a fine wiring layer 62 may be formed in apreferable manner on the second surface 61B of the interlayer insulatinglayer 61.

(2) The thickness T1 from the first surface 37A of the wiring layer 37to the first surface 51A of the interlayer insulating layer 51 is set tobe substantially the same as the thickness T2 from the second surface38B of the wiring layer 38 to the second surface 61B of the interlayerinsulating layer 61. This improves the handling property of thestructure during the manufacturing process.

(3) The cavity 21Y is filled with the interlayer insulating layer 61after a portion of the chip capacitor 40 is buried in the adhesive layer72 (insulating layer 45). This prevents or reduces displacement of thechip capacitor 40 caused by the pressure of the resin that flows intothe cavity 21Y. This improves the connection reliability of the chipcapacitor 40 and the via wires 57.

(4) In the manufacturing method of the conventional semiconductor deviceillustrated in FIGS. 12A to 12D, displacement of the electroniccomponent 92 and the like when the cavity 90X is being filled with theinsulating layer 93 is prevented or reduced by increasing the adhesiveforce (adhesion strength) of the tape 91. In such a case, however,removal of the tape 91 from the core substrate 90 may form a so-calledadhesive deposit in which adhesive residual 91A of the adhesive thatfixes the tape 91 remains on the lower surface of a connection terminalof the electronic component 92, as illustrated in FIG. 12C. The adhesiveresidual 91A adversely affects the electrical connection of theelectronic component 92 and the wiring layer 95, as illustrated in FIG.12D.

In this regards, in the illustrated embodiment, without removing theadhesive layer 72 (insulating layer 45), the insulating layer 45 is leftadhered to the core 21 and the chip capacitor 40. Under this condition,a further insulating layer, that is, the interlayer insulating layer 51is stacked on the first surface 45A of the insulating layer 45. Thisomits the step of removing the adhesive layer 72 and obviates theformation of the adhesive residual 91A. Thus, even when increasing theadhesive strength of the adhesive layer 72, the adhesive residual 91Amay not be formed. Accordingly, the adhesive strength of the adhesivelayer 72 may be increased to prevent or reduce displacement of the chipcapacitor 40 when the cavity 21Y is being filled with the interlayerinsulating layer 61.

(5) The first surface 42A of each connection terminal 42 contacts theupper surface 71A of the tape base 71. Thus, during removal of theadhesive tape 70 (tape base 71 and adhesive layer 72), the first surface42A of each connection terminal 42 is in contact with the tape base 71but not with the adhesive layer 72. This prevents or reduces residual ofthe adhesive layer 72 (insulating layer 45) on the first surface 42A ofeach connection terminal 42 after removal of the tape base 71. Thus,satisfactory electrical connection is obtained between the chipcapacitor 40 and the wiring layer 52 (via wires 57).

(6) In the manufacturing method of the conventional semiconductor deviceillustrated in FIGS. 12A to 12D, the heat history differs between theinsulating layer 93, with which the cavity 90X is filled and whichcovers the upper surface 90B of the core substrate 90, and theinsulating layer 94, which covers the lower surface 90A of the coresubstrate 90 after removal of the tape 91. For example, the insulatinglayer 93 is exposed to heat twice such as during thermal curing, whereasthe insulating layer 94 is exposed to heat once such as during thermalcuring. The difference in the heat history between the insulating layers93 and 94 results in different surface conditions between the insulatinglayers 93 and 94 located above and below the core substrate 90. Thisresults in variations in the conditions for forming the wiring layers onthe insulating layers 93 and 94.

In this regards, in the present example, the interlayer insulating layer51, which is on the side of the first surface 35A of the core 21, andthe interlayer insulating layer 61, which is on the side of the secondsurface 36B of the core 21, are simultaneously formed after removal ofthe tape base 71. Thus, the interlayer insulating layers 51 and 61,which are formed above and below the core 21, have the same heathistory. In this manner, the wiring layers 52 and 62 on the interlayerinsulating layers 51 and 61 are formed under uniform conditions.Accordingly, the wiring layers 52 and 62 are formed on the interlayerinsulating layers 51 and 61 in a preferable manner.

It should be apparent to those skilled in the art that the presentinvention may be embodied in many other specific forms without departingfrom the spirit or scope of the invention. Particularly, it should beunderstood that the present invention may be embodied in the followingforms.

The first surface 42A of each connection terminal 42 of the chipcapacitor 40 may not be flush with the first surface 37A of the wiringlayer 37. For example, in a first modification, the first surface 42A ofeach connection terminal may project from the first opening of thecavity 21Y to a higher position than the first surface 37A of the wiringlayer 37. A manufacturing method of the wiring substrate in a firstmodification will now be described.

First, referring to FIG. 6A, steps that are similar to those illustratedin FIGS. 3A to 3C are performed to mount the core 21 and the chipcapacitor 40 on the upper surface 72A of the adhesive layer 72 of theadhesive tape 70.

Then, referring to FIG. 6B, when the structure illustrated in FIG. 6A isheated under a temperature of 110° C. to 160° C., the chip capacitor 40and the core 21 are pressed against the adhesive tape 70 (adhesive layer72). The chip capacitor 40 is pressed against the adhesive tape 70 untilthe first surface 42A of each connection terminal 42 contacts the uppersurface 71A of the tape base 71. This entirely buries the chip capacitor40 of the illustrated example in the adhesive layer 72. In the presentstep, the first surface 37A of the wiring layer 37 does not contact theupper surface 71A of the tape base 71. That is, the wiring layer 37 isburied in the adhesive layer 72 so that the first surface 37A of thewiring layer 37 is located at an intermediate position in thethicknesswise direction of the adhesive layer 72. The present stepprojects the first surface 42A of each connection terminal 42 from thefirst surface 37A of the wiring layer 37 toward a direction opposite tothe second surface 36B of the core 21 in a direction opposite to thesecond surface 36B of the core 21 (toward the lower side).

As illustrated in FIG. 6C, the tape base 71 illustrated in FIG. 6B isthen removed from the adhesive layer 72. As a result, the insulatinglayer 45 covers the first surface 35A of the insulating layer 35,portions of the walls of the cavity 21Y, the first surface 37A and theside surfaces of the wiring layer 37, the second surface 42B and theside surfaces of each connection terminal 42, and all the surfaces ofthe capacitor body 41 exposed from each connection terminal 42. Thefirst surface 42A of each connection terminal 42 is exposed from theinsulating layer 45. Then, a roughening process is performed on eachconnection terminal 42 that is exposed from the insulating layer 45.

Then, referring to FIG. 6D, in the same manner as illustrated in FIG.4C, the interlayer insulating layer 51 is formed on the first surface45A of the insulating layer 45. This fills the cavity 21Y exposed fromthe insulating layer 45 with the interlayer insulating layer 51.Further, the interlayer insulating layer 61 is formed on the secondsurface 36B of the insulating layer 36. Preferably, the thickness of theinterlayer insulating layer 51 and the thickness of the interlayerinsulating layer 61 are set so that the thickness from the first surface37A of the wiring layer 37 to the first surface 51A of the interlayerinsulating layer 51 is substantially equal to the thickness from thesecond surface 38B of the wiring layer 38 to the second surface 61B ofthe interlayer insulating layer 61.

Next, referring to FIG. 7A, in the same manner as the step illustratedin FIG. 4D, for example, laser processing is performed to form the viaholes VH1 at certain locations in the insulating layer 45 and theinterlayer insulating layer 51 to expose portions of the first surface37A of the wiring layer 37. The via holes VH1 extend through theinsulating layer 45 and the interlayer insulating layer 51. Further,laser processing is performed to form the via holes VH2 at certainlocations in the interlayer insulating layer 61 to expose portions ofthe second surface 38B of the wiring layer 38. The via holes VH2 extendthrough the interlayer insulating layer 61.

Then, referring to FIG. 7B, for example, a semi-additive process isperformed to form the via wires 57 in the via holes VH1, and stack thewiring layer 52, which is electrically connected to the wiring layer 37or the connection terminals 42 through the via wires 57, on the firstsurface 51A of the interlayer insulating layer 51. Further, for example,a semi-additive process is performed to form the via wires 67 in the viaholes VH2, and stack the wiring layer 62, which is electricallyconnected to the wiring layer 38 through the via wires 67, on the secondsurface 61B of the interlayer insulating layer 61.

Subsequently, steps similar to those illustrated in FIGS. 5B and 5C areperformed to manufacture the wiring substrate 20 of the firstmodification and the semiconductor device 10 as illustrated in FIG. 7C.

The chip capacitor 40 may not be buried in the adhesive layer 72 so thatthe first surface 42A of each connection terminal 42 contacts the uppersurface 71A of the tape base 71. For example, in a second modification,the chip capacitor 40 is buried in the adhesive layer 72 so that thefirst surface 42A of each connection terminal 42 does not contact theupper surface 71A of the tape base 71. A manufacturing method of awiring substrate in a second modification will now be described.

First, referring to FIG. 8A, steps similar to those illustrated in FIGS.3A to 3C are performed to mount the core 21 and the chip capacitor 40 onthe upper surface 72A of the adhesive layer 72 of the adhesive tape 70.

Then, referring to FIG. 8B, when the structure illustrated in FIG. 8A isheated under a temperature of 110° C. to 160° C., the chip capacitor 40and the core 21 are pressed against the adhesive tape 70 (adhesive layer72). Here, the first surface 42A of each connection terminal 42 does notcontact the upper surface 71A of the tape base 71. That is, theconnection terminals 42 are buried in the adhesive layer 72 so that thefirst surface 42A of each connection terminal 42 is located at anintermediate position in the thicknesswise direction of the adhesivelayer 72. In the same manner as the connection terminals 42, in theillustrated example, the first surface 37A of the wiring layer 37 doesnot contact the upper surface 71A of the tape base 71. For example, thechip capacitor 40 and the core 21 are buried in the adhesive layer 72 sothat the first surface 42A of each connection terminal 42 is flush withthe first surface 37A of the wiring layer 37. Then, for example, theadhesive layer 72 is thermally cured to form the insulating layer 45.

Referring to FIG. 8C, the tape base 71 illustrated in FIG. 8B is removedfrom the insulating layer 45. As a result, the insulating layer 45covers the first surface 35A of the insulating layer 35, portions of thewalls of the cavity 21Y, the first surface 37A and the side surfaces ofthe wiring layer 37, and all surfaces of the chip capacitor 40.

Then, in the same manner as illustrated in FIG. 4C, the interlayerinsulating layer 51 is formed on the first surface 45A of the insulatinglayer 45. This fills the cavity 21Y exposed from the insulating layer 45with the interlayer insulating layer 51. Further, the interlayerinsulating layer 61 is formed on the second surface 36B of theinsulating layer 36. The cavity 21Y exposed from the insulating layer 45is filled with the interlayer insulating layer 61.

Referring to FIG. 8D, in the same manner as the steps illustrated inFIGS. 7A and 7B, the wiring layer 52 is formed on the first surface 51Aof the interlayer insulating layer 51. The wiring layer 52 is connectedto the wiring layer 37 or the connection terminals 42 through the viawires 57, which extend in the thicknesswise direction through theinsulating layer 45 and the interlayer insulating layer 51. Further, thewiring layer 62 is formed on the second surface 61B of the interlayerinsulating layer 61. The wiring layer 62 is connected to the wiringlayer 38 through the via wires 67, which extend in the thicknesswisedirection through the insulating layer 61.

Subsequently, steps similar to those illustrated in FIGS. 5B and 5C areperformed to manufacture the wiring substrate 20 of the secondmodification and the semiconductor device 10.

In the above embodiment, the chip capacitor 40 may not be entirelyburied in the adhesive layer 72. For example, in a third modification,only a portion of the chip capacitor 40 is buried in the adhesive layer72, and a portion of the chip capacitor 40 is covered by the insulatinglayer 45 in the cavity 21Y.

For example, as illustrated in FIG. 9A, the insulating layer 45 may beformed to entirely cover the side surfaces of each connection terminal42 of the chip capacitor 40. For example, in the cavity 21Y, theinsulating layer 45 may be formed to fill the space between the wall ofthe cavity 21Y and the chip capacitor 40. In the illustrated example,the second surface 45B of the insulating layer 45 is substantially flushwith the second surface 42B of each connection terminal 42. In thiscase, the second surface 42B of each connection terminal 42 and thesecond surface 41B of the capacitor body 41 are exposed from theinsulating layer 45. In this case, the cavity 21Y exposed from theinsulating layer 45 is filled with the interlayer insulating layer 61that covers the second surface 42B of each connection terminal 42 andthe second surface 41B of the capacitor body 41.

In this manner, the insulating layer 45 is formed in a portion of thecavity 21Y, for example, in a space between the wall of the cavity 21Yand the chip capacitor 40. This reduces the space that is filled withthe interlayer insulating layer 61. Thus, advantage (1) of the aboveembodiment is obtained.

In the above embodiment and modifications, among the first surface 42Aand the second surface 42B of each connection terminal 42, the via wires57 are formed only at the side of the first surface 42A. Instead, forexample, via wires may be formed at the two sides of the first surface42A and the second surface 42B of each connection terminal 42. Such awiring substrate may be formed as described below.

First, as illustrated in FIG. 10A, steps similar to those illustrated inFIGS. 3A to 4C are performed to obtain a structure similar to thatillustrated in FIG. 4C. For example, the interlayer insulating layer 51is formed to cover the first surface 45A of the insulating layer 45, thefirst surface 42A of each connection terminal 42, and the first surface37A of the wiring layer 37. Further, the interlayer insulating layer 61is formed to cover second surface 36B of the core 21 and the wiringlayer 38. The cavity 21Y exposed from the insulating layer 45 is filledwith the interlayer insulating layer 61.

Then, referring to FIG. 10B, for example, laser processing is performedto form the via holes VH1 at certain locations in the interlayerinsulating layer 51 to expose portions of the first surface 37A of thewiring layer 37 or a portion of the first surfaces 42A of eachconnection terminal 42. Further, for example, laser processing isperformed to form the via holes VH2 at certain locations in theinterlayer insulating layer 61 to expose portions of the second surface38B of the wiring layer 38. Additionally, for example, laser processingis performed to form via holes VH3 at certain locations in theinterlayer insulating layer 61 and the insulating layer 45 to exposeportions of the second surface 42B of the connection terminals 42. Thevia holes VH3 extend through the interlayer insulating layer 61 and theinsulating layer 45.

Then, referring to FIG. 10C, for example, a semi-additive process isperformed to form the via wires 57 in the via holes VH1, and form thewiring layer 52, which is electrically connected to the wiring layerthrough the via wires 57, on the first surface 51A of the interlayerinsulating layer 51. Further, for example, a semi-additive process isperformed to form the via wires 67 in the via holes VH2, and stack thewiring layer 62, which is electrically connected to the wiring layer 38through the via wires 67, on the second surface 61B of the interlayerinsulating layer 61. Additionally, for example, a semi-additive processis performed to form via wires 67A in the via holes VH3, and stack thewiring layer 62, which is electrically connected to the wiring layer 38through the via wires 67A, on the second surface 61B of the interlayerinsulating layer 61.

Subsequently, steps similar to those illustrated in FIGS. 5B and 5C areperformed to manufacture the wiring substrate and semiconductor deviceof the present modification.

The wiring substrate 20 of the above embodiment and modificationsincorporates the chip capacitor 40, which is thinner than the core 21.Instead, the wiring substrate 20 may incorporate, for example, a chipcapacitor 40 that is thicker than a core 21. Such a wiring substrate maybe formed as described below.

As illustrated in FIG. 11A, a core 80 is first prepared. The core 80 maybe manufactured, using the known art, to include a core substrate 81,through-core electrodes 82 extending through the core substrate 81 inthe thicknesswise direction, a wiring layer 83 formed on a first surface81A of the core substrate 81, and a wiring layer 84 formed on a secondsurface 81B of the core substrate 81 and connected to the wiring layer83 through the through-core electrodes 82. Then, a cavity 80Y is formedin the core 80 (core substrate 81) to open at locations corresponding tothe mounting position of the chip capacitor 40. The cavity 80Y may beformed, for example, by performing router processing, die processingthat uses a die, laser processing, drilling, or the like.

As illustrated in FIG. 11A, an adhesive tape 70 is arranged at the sideof the first surface 81A of the core 80, that is, the side of the firstsurface 81A of the core substrate 81. The adhesive tape 70 is arrangedwith the adhesive layer 72 facing toward the upper side so that theadhesive layer 72 faces the core substrate 81.

Then, referring to FIG. 11B, in the same manner as the steps illustratedin FIGS. 3B and 3C, the adhesive tape 70 is applied to the first surface83A of the wiring layer 83 to obtain the structure in which the chipcapacitor 40 is mounted on the adhesive layer 72 exposed from the cavity80Y of the core 80. Then, in the same manner as the step illustrated inFIG. 3D, when the structure is heated to 110° C. to 160° C., the chipcapacitor 40 and the core 80 are pressed against the adhesive tape 70(adhesive layer 72). As a result, the first surface 81A of the coresubstrate 81, the first surface 83A of the wiring layer 83, the firstsurface 41A of the capacitor body 41, and the first surface 42A of eachconnection terminal 42 press the adhesive layer 72, which is in thesemi-cured state. This spreads the adhesive layer 72 in the planardirection. The spread adhesive layer 72 enters the cavity 80Y so thatthe space between the chip capacitor 40 and the wall of the cavity 80Yis partially filled with the adhesive layer 72. In the illustratedexample, the adhesive layer 72, which spreads in this manner, coversportions of the side surfaces of the chip capacitor 40, and the adhesivelayer 72 covers portions of the walls of the cavity 21Y. In the presentstep, the chip capacitor 40 is pressed against the adhesive layer 72until a portion of the chip capacitor 40 is buried in the adhesive layer72, which is in the semi-cured state. Further, in the present steps, thechip capacitor 40 and the core 80 are pressed against the adhesive tape70 until the first surface 42A of each connection terminal 42 and thefirst surface 83A of the wiring layer 83 contact the upper surface 71Aof the tape base 71. Then, for example, a thermosetting process isperformed thermally cure the adhesive layer 72 and form the insulatinglayer 45.

Consequently, in the chip capacitor 40 of the illustrated example, aportion of each connection terminal 42 at the side of the second surface42B (e.g., upper surface) projects toward the upper side from the cavity80Y. For example, the chip capacitor 40 projects toward the upper sidefrom the second surface 81B of the core substrate 81 and from a secondsurface 84B (e.g., upper surface) of the wiring layer 84.

Then, as illustrated in FIG. 11C, the tape base 71 illustrated in FIG.11B is removed from the adhesive layer 72. As a result, the insulatinglayer 45 covers the first surface 81A of the core substrate 81, portionsof the walls of the cavity 80Y, the side surfaces of the wiring layer83, portions of the side surfaces of the chip capacitor 40, and thefirst surface 41A of the capacitor body 41.

Next, in the same manner as the step illustrated in FIG. 4C, theinterlayer insulating layer 51 is formed on the first surface 45A of theinsulating layer 45. The interlayer insulating layer 61 is formed on thesecond surface 81B of the core substrate 81 to cover the chip capacitor40, which is exposed from the insulating layer 45, and the wiring layer84. Further, the cavity 80Y exposed from the insulating layer 45 isfilled with the interlayer insulating layer 61. The interlayerinsulating layer 61 entirely covers the chip capacitor 40 exposed fromthe insulating layer 45. That is, the chip capacitor 40 exposed from theinsulating layer 45 is buried in the interlayer insulating layer 61. Inother words, even when a portion of the chip capacitor 40 projectstoward the upper side from the second surface 81B of the core substrate81, the projecting chip capacitor 40 may be buried in the interlayerinsulating layer 61. The thickness corresponding to the projectingamount may be absorbed by the interlayer insulating layer 61.

Then, referring to FIG. 11D, in the same manner as the steps illustratedin FIGS. 4D and 5A, for example, a semi-additive process is performed toform the wiring layer 52, which is connected to the wiring layer 83 orthe connection terminals 42 through the via wires 57 extending throughthe interlayer insulating layer 51 in the thicknesswise direction, onthe first surface 51A of the interlayer insulating layer 51. Further,for example, a semi-additive process is performed to form the wiringlayer 62, which is connected to the wiring layer 84 through the viawires 67 extending through the interlayer insulating layer 61 in thethicknesswise direction, on the second surface 61B of the interlayerinsulating layer 61. Additionally, for example, a semi-additive processis performed to form the wiring layer 62, which is connected to theconnection terminals 42 through the via wires 67A extending through theinterlayer insulating layer 61 in the thicknesswise direction, on thesecond surface 61B of the interlayer insulating layer 61.

Subsequently, steps similar to those illustrated in FIGS. 5B and 5C areperformed to manufacture the wiring substrate and the semiconductordevice of the present modification.

In the above embodiments and modifications, the chip capacitor 40including the two connection terminals 42 is incorporated in the wiringsubstrate 20. Instead, for example, an electronic component such as acapacitor including three or more connection terminals 42 may beincorporated in the wiring substrate 20.

In the above embodiments and modifications, the chip capacitor 40 isincorporated in the wiring substrate 20. However, an electroniccomponent such as a chip resistor, an inductor, a semiconductor device(LSI), and the like may be incorporated in the wiring substrate 20.

In the above embodiments and modifications, one electronic component(chip capacitor 40) is incorporated in the wiring substrate 20. Instead,a wiring substrate may incorporate, for example, two or more electroniccomponents. Further, more than one type of electronic component may beincorporated in the same wiring substrate.

In the above embodiments and the modifications, the structure of thecore 21 at the inner side of the outermost wiring layers 37 and 38 isnot particularly limited. In the same manner, the structure of the core80 at the inner side of the outermost wiring layers 83 and 84 is notparticularly limited. In other words, the structure of the cores 21 and80 at the inner side of the outermost wiring layers is not particularlylimited as long as at least the outermost wiring layers 37 and 38(wiring layers 83 and 84) are electrically connected to each otherthrough the interior of the substrate and the cavity 21Y (80Y) isformed. For example, the structure and the material of the coresubstrates 31 and 81 are not particularly limited. The number of wiringlayers and insulating layers, the layout of the wiring, and the like atthe inner side of the cores 21 and 80 may be changed in various manners.Alternatively, the core 21 may be a coreless substrate that does notinclude the core substrate 31.

In the above embodiments and modifications, the through-core electrodes39 are formed to fill the through holes 21X. Instead, for example, thethrough-core electrodes 39 may be formed as conformal vias. In otherwords, the shape of the through-core electrode 39 is not particularlylimited as long as the through-core electrode 39 covers the wall surfacein each through hole 21X and electrically connects the wiring layers 37and 38 respectively formed on the first surface 35A and the secondsurface 36B of the core 21. Similar changes may also be made to thethrough-core electrode 82.

The number of the wiring layers 52, 54, and 56 and the interlayerinsulating layers 51, 53, and 55, the wiring layout, and the like in thewiring structure 22 of the above embodiments and modifications may bechanged in various manners.

The number of wiring layers 62, 64, and 66 and the interlayer insulatinglayers 61, 63, and 65, the wiring layout, and the like in the wiringstructure 23 of the above embodiments and modifications may be changedin various manners.

The cavities 21Y and 80Y of the cores 21 and 80 in the above embodimentsand modifications is formed to have substantially rectangularcross-sections. Instead, for example, the cavities 21Y and 80Y may beformed to have substantially trapezoidal cross-sections in the samemanner as the via holes VH1 and the like. Further, the cavities 21Y and80Y may be formed to have substantially drum-shaped cross-sections.

The above embodiments and modifications are embodied in a manufacturingmethod of a single semiconductor device but may be embodied in amanufacturing method of a batch of semiconductor devices.

Changes may be made to the number of semiconductor chips on the wiringsubstrate 20 of the semiconductor device 10 in the above embodiments andmodifications and the mounting mode of the semiconductor chip (e.g.,flip-chip mounting, wire bonding, or a combination of flip-chip mountingand wire bonding) and the like.

For purposes of clarification and consistency between the descriptionand the claims, it is noted that the chip capacitor 40, described above,corresponds to, and represent example of an electronic component recitedin the claims. Similarly, the wiring layers 37 and 83 are each anexample of a first wiring layer. The wiring layers 38 and 84 are each anexample of a second wiring layer. The wiring layer 52 is an example of athird wiring layer. The wiring layer 62 is an example of a fourth wiringlayer. The insulating layer 45 is an example of a first insulatinglayer. The interlayer insulating layer 51 is an example of a secondinsulating layer. The interlayer insulating layer 61 is an example of athird insulating layer. The via wires 57 are each an example of a firstvia wire. The via wires 67 are each an example of a second via wire.

The disclosure further encompasses various example(s) described below.

[Clause 1] According to one embodiment, a manufacturing method of awiring substrate includes: forming a cavity that extends through a coreincluding a first surface, a second surface, a first wiring layer, and asecond wiring layer, wherein the second surface is located at anopposite side of the first surface, the first wiring layer is formed onthe first surface, and the second wiring layer is formed on the secondsurface; covering the cavity with a tape including an adhesive firstinsulating layer and a tape base, wherein the first insulating layer isadhered to the first surface of the core; arranging an electroniccomponent on the first insulating layer exposed from the cavity; pushingthe core and the electronic component so as to bury the part of theelectronic component and the first surface of the core in the firstinsulating layer; removing the tape base from the core; forming a secondinsulating layer and a third insulating layer simultaneously, whereinthe second insulating layer covers a first surface of the firstinsulating layer, which is located on the first surface of the core,wherein the third insulating layer covers the second surface of thecore, and wherein a portion of the cavity is filled with the firstinsulating layer and the remainder of the cavity that is not filled withthe first insulating layer is filled with the third insulating layer;forming a first via hole, which extends through at least the secondinsulating layer and exposes the electronic component, and a second viahole, which extends through the third insulating layer and exposes thesecond wiring layer; forming a first via wire in the first via hole;forming a third wiring layer on the second insulating layer, wherein thethird wiring layer is electrically connected to the electronic componentthrough the first via wire; forming a second via wire in the second viahole; and forming a fourth wiring layer on the third insulating layer,wherein the fourth wiring layer is electrically connected to the secondwiring layer through the second via wire.

[Clause 2] In the method according to clause 1, it is preferable thatthe pushing the electronic component includes burying the electroniccomponent in the first insulating layer until a connection terminal ofthe electronic component contacts the tape base.

[Clause 3] In the method according to clause 1, it is preferable thatforming the second insulating layer and the third insulating layerincludes setting a thickness of the second insulating layer and athickness of the third insulating layer so that a thickness of thesecond insulating layer over the first wiring layer is equal to athickness of the third insulating layer over the second wiring layer.

[Clause 4] In the method according to clause 1, it is preferable thatthe electronic component includes surfaces located in the cavity, andthe pushing the electronic component includes entirely covering thesurfaces of the electronic component located in the cavity with thefirst insulating layer.

The present examples and embodiments are to be considered asillustrative and not restrictive, and the invention is not to be limitedto the details given herein, but may be modified within the scope andequivalence of the appended claims.

The invention claimed is:
 1. A wiring substrate comprising: a coreincluding a first surface, a second surface, and a cavity, wherein thesecond surface is located at an opposite side of the first surface, andthe cavity extends through the core in a thicknesswise direction andincludes a first opening in the first surface and a second opening inthe second surface; a first wiring layer formed on the first surface ofthe core; a second wiring layer formed on the second surface of thecore; an electronic component partially accommodated in the cavity andincluding a projected portion projected from the first opening of thecore; a first insulating layer covering over the first wiring layer andthe first surface of the core, wherein the first insulating layer coversat least a portion of a side surface of the electronic component andfills a portion of the cavity; a second insulating layer that covers afirst surface of the first insulating layer; a plurality of first viawires each extending through the first and second insulating layers inthe thicknesswise direction, wherein the first wiring layer and theelectronic component are electrically connected to different ones of theplurality of first via wires; a third insulating layer that covers thesecond surface of the core, wherein the remainder of the cavity that isnot filled with the first insulating layer is filled with the thirdinsulating layer; a third wiring layer formed on the second insulatinglayer and electrically connected to the electronic component and thefirst wiring layer through the different ones of the plurality of firstvia wires; a second via wire that extends through the third insulatinglayer; and a fourth wiring layer formed on the third insulating layerand electrically connected to the second wiring layer through the secondvia wire.
 2. The wiring substrate according to claim 1, wherein athickness of the second insulating layer over the first wiring layer isequal to a thickness of the third insulating layer over the secondwiring layer.
 3. The wiring substrate according to claim 1, wherein thefirst insulating layer entirely covers a side surface of the projectedportion of the electronic component.
 4. The wiring substrate accordingto claim 1, wherein the electronic component includes surfaces locatedin the cavity, and the first insulating layer entirely covers thesurfaces of the electronic component located in the cavity.
 5. Thewiring substrate according to claim 1, wherein the first insulatinglayer includes a first portion sandwiched between the first wiring layerand the second insulating layer.
 6. The wiring substrate according toclaim 5, wherein the first insulating layer includes a second portionsandwiched between the first surface of the core and the secondinsulating layer, the first portion of the first insulating layer has afirst thickness, and the second portion of the first insulating layerhas a second thickness greater than the first thickness.